Dupont said he will step down from his position on 31 January 2015, and will be replaced by Davy, who was appointed to the South West Water board seven years ago.
She will take on the role immediately upon Dupont’s retirement, a statement from the company said.
Ken Harvey, chairman of Pennon Group, said: “David has made a very significant contribution to the success of Pennon over many years.
“His careful management of the group’s finances; his contribution to the strategic development of both South West Water and Viridor; and the productive relationships he has had with the City and investors has ensured that Pennon Group remains a well respected company in its sector.”
He added: “David’s decision to retire next January is therefore timely in that it will allow his successor to actively contribute to the next phases of development of both South West Water and Viridor.”
Analysts at RBC Capital said in an investor note on Tuesday morning that although Dupont’s retirement will “undoubtedly be a loss for the group”, they view Davy’s appointment as a “positive” move for the company.
“Most recently, she has been credited for having led SWW in its AMP6 business plan submission, where SWW was the only UK water and sewerage company to have received an enhanced status,” the note said.